It is not clear what features will not be available, but we hope that this is not a situation like Windows Phone 7 to Windows Phone 8 upgrade, where some devices have been left with a Windows Phone 7.8 update which contained only a few minor features eight windows phone. This is not something that Microsoft will want to repeat, so it is likely that the company will do everything to ensure that Windows 10 running on Windows Phone 8 devices with 512MB of RAM. Microsoft had already won all Lumia Windows Phone 8 devices will be upgraded to Windows 10 and Belfiore noted that the company is just working on right now and it's a "ambition" for Windows 10 on low specification devices .
Windows Phone device most popular Microsoft is the Lumia 520 with 512 MB of RAM, followed shortly by the Lumia 630, Lumia 625 and Lumia 530 - all with 512 MB of RAM. It seems that the majority of the popular Windows Phone devices will not get any Windows 10 new features once they are available. Microsoft plans to preview these features very soon, but not all devices. Belfiore noted there will be a "subset" of the phones compatible with Windows 10 overview, and The Verge understands that will focus on devices like the Lumia 730 and Lumia 830 recently delivered. Microsoft is close to the release of its Windows 10 preview for phones, and it is likely that it will be available this week, providing testing goes well internally.